Bethany Shipsey died in Worcestershire Royal hospital on 15 February last year, a day described by hospital staff as overwhelming. She had swallowed tablets she bought online from eastern Europe that contained the industrial substance DNP.

An animal welfare activist, Shipsey was described by her mother, Carole, as a gifted photographer and “full of life”.

She said her daughter suffered mental health problems when she faced bullying on social media and broke up with her boyfriend. The inquest was told that Shipsey had been raped by a previous partner and was on home leave from a psychiatric ward when she took the pills.

The coroner, Geraint Williams, recorded a verdict of suicide, but also criticised failings at the hospital where he said the care Shipsey received was “significantly substandard”.

However, Williams said it was not possible to conclude that Shipsey would have survived if the treatment she received had been up to scratch.

Carole Shipley, herself a nurse, told the inquest that she took her daughter’s pulse and even changed the electrodes on a monitor because A&E staff were too busy. She and her husband, Doug, also claimed there was a delay before their daughter was put in a resuscitation room and she was moved from there because other patients were considered more seriously ill.

In a statement read after the conclusion of the inquest, Shipsey’s parents expressed their disappointment at Williams’s findings and blamed the standard of care she received at the hospital.

“We do not feel that the coroner’s conclusion reflected the evidence that was heard during the inquest ... Bethany’s basic human right to life was breached in the very place you would expect it to be preserved,” they told Sky News.

Dr Alireza Niroumand, an emergency junior medical doctor who treated Shipsey, told the inquest it was one of the busiest days he had experienced. He said that he was not familiar with the pills Shipsey had taken and, under questioning, said he should have consulted the poisons department in order to fully understand the drug.

Kirsty South, a senior sister at the hospital and the coordinator of the A&E department at the time Shipsey was admitted, said: “We were often unable to meet the quality access standards that day. It was one of the most challenging shifts we have worked. It was more than busy.”

In December, it emerged that the trust had to turn patients away from A&E units 13 times in a week, including four times in a day, as snow left it facing “extremely challenging” conditions.